pub fn sitka() -> Result<DataFrame, PolarsError>Expand description
§Growth Curves for Sitka Spruce Trees in 1988
§Description:
The ‘Sitka’ data frame has 395 rows and 4 columns. It gives repeated measurements on the log-size of 79 Sitka spruce trees, 54 of which were grown in ozone-enriched chambers and 25 were controls. The size was measured five times in 1988, at roughly monthly intervals.
§Usage:
Sitka
§Format:
This data frame contains the following columns:
- ‘size’ measured size (height times diameter squared) of tree, on log scale.
- ‘Time’ time of measurement in days since 1 January 1988.
- ‘tree’ number of tree.
- ‘treat’ either ‘“ozone”’ for an ozone-enriched chamber or ‘“control”’.
§Source:
P. J. Diggle, K.-Y. Liang and S. L. Zeger (1994) Analysis of Longitudinal Data. Clarendon Press, Oxford
§References:
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
§See Also:
‘Sitka89’.